Generally, telecommunications systems provide the ability for two or more people or machines (e.g., computerized or other electronic devices) to communicate with each other. Many types of telecommunications systems exist in the prior art. Examples include telephone systems and networks, data communications systems, computer networking systems such as the Internet, wireless and satellite communications systems, and so forth. Each of these systems is inherently enabled or can be retrofitted via software and/or electronic hardware to provide telecommunications services between persons or devices coupled to such systems. Telecommunications systems and services in a general sense are sometimes limited to simple voice or audio communications, although such systems may support communications of other types of data such as signaling and protocol data, video data, and computer or device application data.
FIG. 1 illustrates an example of a prior art telephone network 101 that is a common example of a telecommunications system in widespread use throughout the world. As illustrated, the telephone network 101 includes a number user telephony devices 105 through 108 (e.g., telephones) that inter-connect to various tandem or central offices 110 through 113. Communications media (e.g., telephone lines, wireless links, and/or the like) interconnect the offices 110 through 113 to one another to form a public switched telephone network (PSTN) 101-A. The central or tandem offices 110 through 113 may be replaced, for example, private branch exchanges, PSTN control hardware or other telephone switching equipment. Such equipment is typically owned by a telephone service provider. Users of the telephone network 101 typically subscribe to a telecommunications service (e.g., telephone service) which the telephone service provider offers.
The telephone network 101 also includes a PSTN signaling network 101-B that operates over the same medium as the PSTN 101-A. The PSTN signaling network 101-B generally supports a standard signaling technique such as Signaling System Seven (SS7) or User-to-Network interfaces between the offices 110 through 113 and the user telephony devices 105 through 108 to support call connections (e.g., telephone calls, not specifically shown) between the user telephony devices 105 through 108. The user telephony devices 105 through 108 may be telephone handsets, telephone answering machines, fax machines, modems or other such devices.
The telephone network 101 is an example of a connection-based network. To communicate in a connection-based network, the network components (telephony devices and switching equipment in this example) establish a dedicated connection or path between two or more end points of communication. The dedicated connection, also called a circuit or switched circuit generally remains active or established during the duration of a telecommunications session between parties using the connection.
By way of example, in FIG. 1, suppose a user (not shown) of the user telephony device 105 desires to communicate with a user (not shown) of the user telephony device 108. To do so, the user of user telephony device 105 picks up a handset of the user telephony device 105. This action causes the central office 113 to establish a dedicated connection (a completed circuit) to the central office 113 for use by the user telephony device 105. Thereafter, when the user of telephony device 105 enters connection establishment information in the form of a phone number corresponding to the user telephony device 108, the central office 113 extends the dedicated connection through the PSTN 101-A to the central office 112 using signaling provided by the PSTN signaling network 101-B. When the central office 112 receives this signaling, the central office 112 completes the connection to the user telephony device 108 causing it to ring. When a user or machine answers the user telephony device 108 by lifting the handset for example, this action fully establishes an end-to-end connection between the user telephony device 105 and the user telephony device 108. The dedicated connection remains established for the duration of the communications session between the users using the user telephony devices 105 and 108, even if they are not speaking or otherwise communicating at all times.
Typically in a connection-based network such as telephone network 101, the network components (e.g., switching offices) can identify various active dedicated communications sessions by the circuit or wire identifiers of the physical wires with which the network 101 uses to transport communications for those sessions. A central office, for example, can identify one particular segment of a connection circuit used for communications with a user telephony device by the telephone number associated with the segment that leads to the device. Most central office switching equipment can be programmed to identify a particular call identifier such as a telephone number with a particular circuit associated with a telephony device located at the end of the circuit. When the central office equipment receives a request to establish a call connection to a telephony device on a particular circuit, the central office can activate the circuit to form a completed circuit or call connection to the telephony equipment on the opposing end of the circuit.
Prior art telephone switching offices and equipment are able to combine certain signaling techniques such as those supported by the PSTN signaling network 101-B with the ability to identify connection segments or individual circuits in order to support various prior art extended telecommunication services. Such services provide features within the telephone network beyond the ability of the network to support simple end to end telephone calls. For example, many prior art telephone networks support calling features such as call waiting, call forwarding, missed call call-back (also known as “star-69”), toll-free “800” numbers, scheduled wake-up calls, conference calling, and so forth. A prior art connection-based telephone network provides each of these types of services based on connection-based network signaling which may occur before, during, and/or after the actual establishment or activation of one or more individual circuits or call connections to one or more telephony devices (e.g., before, during or after placement of a telephone call). For example, a prior art toll-free “800” number service uses signaling before placing a call connection to perform a “lookup” operation of the toll-free phone number in order to reverse call charges to the receiver of the call (identified by the receiving call circuit) instead of charging the sender or calling party. A prior art call waiting service uses signaling during a call connection to notify a user in the active call connection of another incoming call connection for the same circuit. A scheduled wake up call service provides call signaling after one call connection is made (the call to schedule the wake up call) but before another future call connection is placed (the actual wake up call).
In each of these examples, a signaling system within the telephone network (e.g., 101) provides signaling to support, track, or otherwise manipulate one or more basic dedicated circuits or call connections between one or more telephony devices in the network. In FIG. 1 then, while the PSTN signaling network 101-B may be quite robust to support the aforementioned enhanced calling features, the underlying results from the signaling are essentially to establish one or more call connections across the telephone network 101 to support communications sessions which are typically voice grade.
Generally, large telecommunication service companies (e.g., telephone companies such as AT&T, MCIWorldCom, Bell Atlantic, GTE and the like) own and operate the equipment (e.g., public telephone switching equipment) and media (e.g., telephone lines, satellite links, etc.) that support communications on a telephone network. Such equipment and media is presently widespread in either physical or wireless form throughout much of the United States and the world. As a result, telephone service of some sort, be it physical land-based lines or wireless service (e.g. cellular or satellite) is generally available in most locations. Since service providers have spent significant amounts of time and money to install the existing telephone network infrastructure, much of the equipment from twenty, thirty or more years ago is still in use today to support call connections. Due to such a large investment in the existing systems, public telephone service providers that want to offer advanced calling services in addition to the placement of regular point-to-point public telephone call connections must develop and deploy such services using the existing public telephone infrastructure as a base. That is, if a public telephone service provider desires to support one or more advanced calling services such as those mentioned above, such new services must be fully compatible with the existing public telephone infrastructure or development costs become prohibitive and/or the advanced services might not work properly due to limitations of the existing equipment.
To this end, only highly skilled technicians under the employ of the telephone companies are generally allowed to modify and further develop the existing public telephone software, hardware, and signaling systems such as SS7 that inter-operate and control prior art telephone network switching equipment. Moreover, once a new service such as call waiting has been perfected to work with the existing public telephone infrastructure, deployment of the service to individual consumer telephones requires that the consumer (i.e., public telephone subscriber) notify the public telephone service provider of the desire for the service and also requires the service provider to separately instruct a technician to activate the service for a call connection (e.g., the phone number) associated with that particular individual public telephone subscriber.
In contrast to connection-based networks such as the telephone network 101 in FIG. 1 which operates using a dedicated connection, a connection-less network such as a computer network can support telecommunications services without a single dedicated path to support the communications through the network.
FIG. 2 illustrates an example of a prior art connectionless computer network 140 configured to support telecommunications. The connectionless network 140 includes a plurality of network devices 151 through 155 interconnected via data links (e.g., 150), as well as computer hosts 144 and 145 which in this example each include a respective attached computer telephony device 141, 142. This example shows the connectionless network as an Internet Protocol (IP) network 102 which is a computer network such as the Internet. The network devices 151 through 155 might be routers, for example, which can quickly route data in the form of packets, cells frames or the like between computer hosts 144 and 145 (only two hosts are shown in this example). The computer hosts 144 and 145 can be any type of computer such as personal computers, workstations or the like.
To operate as a telecommunications system, the connectionless computer network 140 can use a technology such as Voice Over IP (VOIP). VOIP is generally provided by a software application (not specifically shown) that executes on the computer hosts 144 and 145. Using a VOIP application, a user (not shown) of computer host 144 can speak into a handset or microphone provided as part of the computer telephony equipment 141. The computer host 144 receives, digitizes and packetizes the voice and transmits the voice data in packets, cells, frames or some other unit (not specifically shown) onto the IP network 102. The routers 151 through 155 can receive and route the various voice data packets through the IP network 102, one by one, until they reach their intended destination computer host 145. Upon receipt of the voice data packets, the destination computer host 145 de-packetizes the voice data and converts it back into an analog signal which is provided to a speaker provided as part of the computer telephony equipment 142 for listening by a recipient user (not shown). Such a system can send voice data in either direction between users thus providing a two-way telecommunications session. In this manner, users are able to speak to each other using computer network communications.
Since the IP network 102 is a connectionless network, each voice data packet sent from the computer host 144 is individually routed through the network 102. Depending upon network congestion (e.g., heavy data packet loads resulting in network devices buffering packets for processing) within the various network devices 151 through 155, each packet may take a different route through the network 102. When a user is not speaking into his or her computer telephony equipment, the computer hosts 144 and 145 and network devices 151 through 155 generally do not transmit packets to one another, hence the name “connectionless” network.
A VOIP software application uses the same packet communications that carry the voice data to perform any required call signaling. This is called “in-band” signaling. For example, if the VOIP application executing on computer host 144 wants to notify the user telephony device 142 of an incoming call, a “new call” packet is sent from the VOIP applications executing on the computer host 144 to host 145. The network 140 routes the new call signaling packet just like another other data packet. A VOIP application can transmit one or more signaling packets during the transmission of voice data packets. In this manner, with respect to the computer network infrastructure (e.g., data links 150 and the individual network devices 151 through 155), call signaling is treated the same as any other type of communications and is generally handled at the software application level.
Prior art protocols have been developed in an attempt to have a general purpose computer system control telephone switching equipment. One such protocol is called PINT, which stands for the PSTN to InterNeT protocol. PINT is a protocol under development by the Internet Engineering Task Force (IETF), which is a standards based organization. PINT defines a protocol to allow certain basic telephone switching services to be controlled via a computer on a connectionless network. The basic service provided by PINT allows a computer system such as a workstation to use PINT commands that are understandable by telephone switching equipment to have that telephone switching equipment establish a single call connection to a telephony device (i.e., a telephone) on a telephone network. PINT thus provides a tool in the form of basic protocol commands for a system developer to interface a computer to PSTN equipment. The PINT protocol specification suggests the ability to use PINT in the creation certain calling services such as click to dial and click to fax, but the implementation of such services is up to system and software designers. The PINT protocol thus provides a framework for interfacing computers to telephone equipment and provides a fundamental building block or function that allows a computer system to cause telephone switching equipment to create one or more call connections on the telephone network.
In the area of prior art private telecommunications systems, developers have created systems that provide calling services that extend beyond the services available in a public switched telephone network. Such private telecommunications systems operate using privately owned and typically more advanced telephone switching equipment commonly known as a “Private Branch Exchange (PBX)” or an “Automatic Call Distributor (ACD)”. A typical PBX or ACD system interconnects a number of advanced PBX telephony devices designed to take advantage of the capabilities that the PBX has to offer. Essentially, the PBX and its associated PBX telephony devices provide a private telephone network. Since such private telecommunications equipment has been more recently developed as compared to conventional public telephone switching equipment that has been in place for sometimes fifty years or more, and since such equipment is intended for private use and control, PBX systems provide more advanced calling services such as call transfer from one PBX telephony device to another, auto-attendant voice messaging systems, and conference calling.
A typical PBX system (PBX and associated PBX telephony devices) is designed for use in a business environment and is quite expensive as compared to telephone equipment that consumers can use on a public switched telephone network. The PBX itself is typically a computer controlled device that may include software and hardware (e.g., electronics) as well as a number of ports for interconnecting the various PBX telephony devices. The PBX typically also provides one or more interfaces to allow the PBX network to be coupled to a PSTN network. Telephone calls that PBX users place between PBX telephony devices are handled completely by the PBX within the PBX network, without the need to complete call connections to public telephone switching equipment (e.g., a tandem or central office).
Some prior art PBX systems provide an interface to a computer system or a computer network. Such an interface can be used to direct the PBX system to place telephone calls between users of the PBX network, and in some cases, between a PBX network user and a person on a telephone that is external to the PBX network.
An example of such a prior art PBX system is disclosed in U.S. Pat. No. 5,991,394 (Dezonno et al.). The system disclosed in Dezonno allows a telephone computer to control an ACD or a PBX under the direction of connections made to the telephone computer from a computer network such as the Internet. In the Dezonno system, for example, a computer user on the Internet can send a call request message via his or her computer to a telephone computer that is interfaced to control the PBX. The call request message instructs the telephone computer to direct the PBX to create a telephone call from a PBX user telephone (e.g., from an agent in a business owning the PBX using an agent telephone coupled to the PBX system) through the PBX and out to a computer user telephone located on a telephone network. Essentially, this allows the computer user to have the business call-back the computer user. The computer user can specify the time at which the call-back is to be made. This allows, for example, the computer user to complete his or her use (e.g., web surfing, reading email, etc.) of the Internet via a dial-up telephone connection to an Internet Service Provider (ISP) over that computer user's telephone line. Since the call-back can be specified to take place in the future, the telephone computer can thereafter detect the time at which to place the call-back and can then instruct the ACD (or PBX) to place the call between the agent's PBX telephone and the computer user's telephone (that was formerly in use to connect to the Internet).